Signal smoke compositions



Patented Nov. 29, 1949 SIGNAL SMOKE COMPOSITIONS John Vinton, SanFrancisco, and Douglas M.

MacMillan, Berkeley, Calif.

No Drawing. Application May 20, 1947,

" Serial No. 749,360

1 Claim.

This invention relates to signal -smoke composition.

It is the main object of our invention to disclose a compositionsuitable for providing a daylight visible redsmoke for use in caseswhere it is necessary to signal the location of a potential danger to aperson at a considerable distance.

It is common practice in the operation of many if not all of therailroads in this country for a train making an unscheduled stop toprovide a signal calculated to appraise a following engineer of the factthat the train ahead constitutes a potential hazard to him. At night,these signals take the form of the standard strontium nitrate fusee, redlights and lanterns of several varieties; there are conventions havingto do with their manner of display, the distance behind the stoppedtrain, etc.

In the case of daylight stoppages, however, it is preferable to use asmoke signal. In our experience, we have knowledge of several railroadaccidents occurring in daylight due to the fact that the followingengineer was unable to see the luminous signal which was displayed in aneffort to stop There has been a real difliculty in securing smokecompositions which will dependably provide a smoke having the proper reddanger color.

It is not feasible to employ lights or other illuminating devices of anycolor since the brightness necessary to render them distinct in daytimeis excessive. We have determined that if a red smoke, visible indaytime, be utilized as a danger signal, it may be observed up to 25times farther than may be the best standard daytime illuminating devicesnow in use.

The following constitutes the formula for our composition.

Dye No. 1-13 parts by weight Dye No. 2-1.8 parts by weight (Rhodamine B)Lactose-8.5 parts by weight Potassium chlorate-7 parts by weight.

In this composition, the lactose is the fuel and the potassium chlorateprovides the oxygen for a controlled nameless combustion. The two dyeshave the following compositions:

Dye No. 1

CH: CH

Dye No. 2 (Rhodamine B) O (I \Omcnm.

OOOH

In our experience it is not permissible to vary substantially from theabove proportions except in the case of the Dye No. 2. Variation in thequantity of this ingredient between reasonable limits has only theeffect of changing the shade of the red of the smoke produced. It ispermissible to vary the portion of this dye between 1.0 and 3.0 parts byweight.

In the preparation of the material, we have found that we can produce aslow-burning composition having a high smoke density by mixing thevarious ingredients in sufficient water to constitute a heavy paste.This paste is dried or is allowed to dry by atmospheric exposure, thenrubbed through a screen having such a mesh as to produce the desiredparticle size, a preferable screen having meshes to the inch. Inaddition to increasing the density of the smoke produced by thecomposition, the preparation as described eliminates the 'dust problemand is thus desirable from this additional consideration.

The composition may be used in any case where it is desired to produce ared smoke. We have particularly in mind, however, the employment 5 ofthis composition in a fusee such as that disclosed in Patent No.3,412,018 issued December 3, 1946, to John Vinton, one of the presentinventors.

We have found that the burning of this com- 10 position as describedabove produces a dense red smoke visible and recognizable as a dangersignal for a long distance even in the brightest daylight. It isbelieved it could never fail to attract attention due to its intense redcolor or to be dis- 15 tinguishable from fires of other origins.

We claim:

The red smoke producing racompositiomeonsisting of a homogeneous mixture'of 'the following ingredients in substantially the PIODOItiOl'lSggo CH30H HsCON=N and Dye No. 2 is COOH JOHN VINTON. DOUGLAS M. MACMIILAN.

REFERENCES CITED 2. The iollowing"referenceszare ofrecord in thefileribf lthisapatentz UNITED STATES PATENTS Number Name Date1',319,'829 -'"Gowdy Oct. 21, 1919 -'r ,2,4 1,1,070 'i-VanyKarner Nov.12, 1946 12311 383 Switzer Mar. 11, 1947 2,417,384 nSwitzer Mar. 11,1947 ";,2,'.419';851 "0181111) Apr. 29, 1947 OTHER REFERENCES ColorIndex (RoweLgpage 190, No. 749. (Copy 30 in-,DivisionL-v43.)

Colored Signal Smokes-Chem; Eng.News;r-ivol.

Lat-Nature;tl9 io pa es 2405-244 :(241; pertinent).-.

